Vibratory telegraphy



I (No Model.)

S. D. FIELD. VIBRATORY TBLEGRAPHY.

No. 496,513. Patented May 2, 1898.

WITNESSES. INVENTOH .6; 5 44; ,0. 521 6 wp/glx A ATTORNEYS.

m: NORRrS PETERS on, PHOTO-H1110" wwmu'rou n4 1;

UNITED; STATES AT NT OFFICE.

STEPHEN n. FIELD, or YONKERS, NEW YORK.

VIBRATO RY TELEG RAPHY.

SPECIFICATION forming part of Letters Patent No. 496,513, dated May 2,1893.

Application filed July 30, 1892.

To all whom it may concern.-

Be it known that I, STEPHEN DUDLEY FIELD, a citizen of the UnitedStates, residing at Yonkers,in the county of Westchester and State ofNew York, have invented certain new and useful Improvements in VibratoryTelegraphy or Telephony; and I do hereby declare the following to be afull, clear, and

exact description of the invention, such as will enable others skilledin the art to which it appertains to make and use the same.

This invention relates to electric signaling, its object being to renderminute electrical vibrations, including those developed in thetransmission of vocal utterances, available for intercommunicationbetween several points or stations.

The invention is carried out by maintaining a succession of rapidvibratory or undulatory electric impulses in a circuit preferablyraising the tension of such impulses by means of a transformer orinduction coil and varying the strength of such impulses by atransmitting apparatus in accordance with the signal to be transmittedwhether vocal or otherwise.

The several features of novelty will be more particularly hereinafterdescribed and definitely indicated in the claims appended to thisspecification.

In the accompanying drawing the figure shows a diagram of a systemembodying my invention.

Referring first to the figure, A and B represent two distant stationsand 0 an intermediate station. At station 0 are two induction coils, thesecondaries of which are connected respectively with the lines extendingto stations A and B, and the primaries of which are connected with alocal circuit including a device for creating rapid vibrations orundulations of a local current. A preferred form of apparatus forcreating these rapid vibrations is my thermic vibrator, comprising aGerman silver wire 1, 2, having one end mounted againsta rubber cushion3 supported in a standard projecting from metallic frame 4, and itsother end made adjust-able so that the tension may be varied. A-threadedrod 5 sliding through a standard on the frame 4 co-operating with anadjusting nut 6 forms a simple and efficient mechanism for drovipingSerial No. 441,756. (No model.)

the necessary adjustment. The cushioned end of the wire carries acontact 7 against which is pendulously supported a co-operating contact8. One of these contacts is preferably formed of carbon though both maybe made of metal. A pivotally supported arm 9 and a regulating weightmounted on a rod 10 afford convenient means of varying the force of thecontact at 7, 8. The primaries of the induction coils are connected inseries and the free terminals are carried respectively to the contact 7and to the frame 4 at the fixed end of the wire. Two local batteries 11,12 are placed at the two sides of the wire, and a wire 13, flexiblyconnected with the wire 1, 2 at or neara central point, forms a bridgebetween the wire and the two primaries 15, 16.

At the stations A and B are provided suitable receiving or transmittingdevices capable of responding to electrical vibrations or undulations orof throwing them upon line. They may be an ordinary magneto telephoneacting as a receiver or transmitter or the usual telephonic outfitcomprising a magneto re ceiver and carbon transmitter. When theapparatus is in its normal condition the batteries 11, 12 dischargingover the circuit l1, 15, 16, 12, 2, 1,heat the German silver wire andcause it to expand; the shunt through contacts 7, 8 carries part of thecurrent away from the wire over the path 9, 4, thus causing the wire tocool and contract. This state of afiairs induces an exceedingly rapidvariation of contact of very high resistance at the points 7,8, thependulous weight being unable to follow the rapid changes in the wire,causing rapid fluctuations in the primaries of induction coils 15, 16,inducing corresponding fluctuations upon the lines; but the vibrationsare so exceedingly rapid as to be inaudible to the intervals when thecircuit is open, and other intervals when it is closed, thus varying theresistance within extremely wide limits. XVhen the points '7, S are infirm contact, the wire 1, 2 is substantially short-eircuited and whenthe points 7, 8 are out of contact the wire 1, 2 must carry the entirecurrent of both batteries. Suppose an electrical vibration proceeds fromstation A, it will induce in the primary of the transformer 15, at O, avibration of low electro-motive-force which will vary the strength ofthe normal current circulating over the local circuit. The bridge Wire13 permits the currents induced by the transmitting vibrations to belocalized in one of the sections 1 or 20f the t-hermic wire, thusavoiding the necessity of their passage through both induction coils,which would weaken their effect by the choking action they would exert.The increased current causes an abnormal expansion of the thermic wireand creates considerable fluctuations of resistance between the contactswhich reacting on the battery circuit and the induction coils relaystrong impulses to station B. k

It is important that the variations of electro-motive-force normallydeveloped by the thermic vibrator should be inaudible t0 the car, sothat, unless signals or vibrations emanating at A or 13 having anaudible rate 0ccupy the line, silence would exist in the receivinginstrument. The pendulously supported contact 8 is well adapted tosecure this result. Eeing mounted on the end of a comparatively long armits inherent rate of vibration will be so slow that the variations ofelectromotive-force which such inherent vibrations impose will notinterfere with perfeet transmission of the signals emanating from one ofthe stations. If the contact 8 were mounted upon an elastic supporthaving an audible rate of vibration or a tone of its own, such tonewould be imposed upon the line.

Having thus described my invention, what I claim as new, and desire tosecure by Letters Patent, is i 1. An electric signaling systemcomprising a line wire including several signaling stations, a thermicvibrator for normally imposing rapid electrical vibrations upon saidline wire, said vibrator comprising a stretched wire mounted oninharmonious supports, an electric generator normally discharging oversaid wire, a pendulous contact having an inaudible rate of "ibrationclosing a short circuit around the wire, and signal transmittinginstruments at the stations for varying the force of the vibrations inaccordance with the signals to be transmitted.

2. A signaling system provided with means for imposing rapid electricalVibrations on lines connecting two or more stations, said meanscomprising a thermic vibrator for varying the resistance of a localcircuit,including the primaries of two or more induction coils, thesecondaries of which charge the line, a bridge wire connccting thethermic wire with a point between the primaries, and an electricgenerator on each side of said bridge wire.

In testimony whereof I affix my signature in presence of two witnesses.

STEPHEN l). FIELD. \Vitnesses:

RonT. II. READ, VIcTon E. BURKE.

